Background and objectives

Although treatment with anti-TNF therapy is effective in controlling disease activity in patients with refractory rheumatoid arthritis (RA), approximately 30% of patients do not respond. Moreover, in certain patients, adjustments in therapy are needed after an initial response. We sought to better delineate this in a cohort of RA patients receiving anti-TNF therapy.

Patients and methods

Sixty-four patients (50 females and 14 males, mean age 52.6 years and mean disease duration 10.3 years), with active rheumatoid arthritis despite treatment with disease-modifying antirheumatic drugs (DMARDs) received infliximab. In these patients, treatment with a mean of 2.9 DMARDs had previously failed. Treatment with methotrexate was continued in 48 patients (mean dose 10.1 mg/wk) and with various DMARDs in 6. Concomitant prednisolone (mean dose 8.5 mg/d) was used in 43 (67.2%). The DAS index (44 joints) was applied to assess clinical efficacy. The dose of infliximab was 3 mg/kg per infusion administered every 8 weeks after the third dose on week 6.

Results

In this cohort, 19 (29.7%) patients discontinued therapy (42% for lack of insurance coverage, 26% because of inefficacy, 21% because of infections and 11% because of allergic reactions). No patient discontinued therapy for any reason after the 30th week. All clinical parameters were significantly improved (P < 0.01) after the fourth infusion. Forty-five patients completed 6 infliximab infusions (mean 30 weeks) and 29 of them 12 infusions (mean 75 weeks of treatment). In the last group, clinical response was sustained throughout the 75 weeks of treatment and the dose of prednisolone was significantly decreased (P < 0.0001) while 24% (6 of 25) of patients discontinued steroids. To achieve clinical response, the frequency of infliximab infusions was increased to every 6 weeks in 31% of patients, while methotrexate was significantly increased in 38% of patients (21 patients, mean dose from 10.1 to 12.3 mg/wk, P < 0.04).

Conclusion

The clinical response of RA patients treated with infliximab is sustained during 75 weeks of treatment. However, in approximately one-third of patients, the frequency of infliximab infusions has to increase after initial response in order to sustain it.